31字符串— string:示例 运行结果为: Length of strobl: 12 Char at index 3 in strobl: S strobl!= strOb2strOb1== strOb3运行结果为： Length of strOb1: 12Char at index 3 in strOb1: s strOb1 != strOb2strOb1 == strOb3 3.1字符串——String：示例